Vehicles which use a base subassembly having independently driven wheels on opposite sides thereof are available on the market today. This general type of steering system is commonly known as the "skid steer" principle. Because such vehicles use an independent axle at each wheel on the opposite sides of the vehicle, large amounts of torque are generated within the frame of the base subassembly. The prior art base subassemblies have generally used a torque tube displaced from the rotational axis of the wheels in an attempt to compensate for the torque applied as the vehicle is operated. This has created problems in that a majority of the torque was applied directly to the frame of the base subassembly without being transmitted to the torque tube. Another problem with these prior art base subassemblies is the lack of accessibility to the components, especially the prime mover, in the base subassembly for maintenance and repair. This has required considerable down time while the subassembly was disassembled to reach the damaged component to repair same. Most of the prior art base subassemblies were designed for a single use so that if an attempt was made to mount different types of accessory equipment thereon as is frequently required in the economical operation of such equipment, this accessory equipment could not easily be mounted on the base subassembly without considerable remanufacture of the subassembly and/or, even if such equipment could be mounted, it could not be used without damage to the base subassembly. The wheel and tire assemblies of the prior art base subassemblies have also been difficult to remove.